The aims of the proposed research are: 1. To study the binding of globin chains to the red cell membrane during sterile incubation in vitro by quantifying ghost protein, hemoglobin, and alpha and beta chains. Specifically, cells from patients with the following disorders will be examined: a. beta-thalassemia minor; b. Iron deficiency anemia; c. sickle cell trait; d. Sickle cell anemia (irreversibly sickled cells). 2. To compare density fractions of normal red cells in regard to: a. Surface topography, using an impermeant probe, 125I-diazotized diiodosulfanilic acid (DD125ISA). b. Effects of sterile incubation in vitro on membrane proteins, hemoglobin, and bound alpha and beta chains. c. Loss of external DD125ISA-labeled proteins during incubation. 3. To use the above techniques for the study of external and internal membrane surfaces of red cells from splenectomized normal subjects and patients with hereditary spherocytosis. 4. To use the above techniques (DD125ISA labeling and quantitative and qualitative analysis of membrane proteins) to identify changes in red cell membranes that may occur with blood storage under usual blood bank conditions. 5. To define and quantify the loss of external (DD125ISA-labeled) red cell membrane proteins that occurs with sterile incubation in vitro with and without depletion of ATP.